When Darren Sproles walked up to the wall to get measured at the Senior Bowl week four years ago, there were plenty of chuckles among the gathered NFL executives and scouts.

The markings on the wall only went down to 5 feet, 8 inches. A ruler had to be found to make up the difference and properly document Sproles at 5-6.

The laugh now belongs to Sproles.

The kid is going to be paid, perhaps by one of the personnel men who were in that Mobile, Ala., room wondering if the diminutive running back out of Kansas State could make it in the NFL.

Primarily a kick returner most of his first three seasons in the NFL (he lost the 2006 season to a broken leg), Sproles has never made an NFL start and only twice this season touched the ball from scrimmage more than 10 times in a game.

Yet, here he is on the verge of becoming an unrestricted free agent, having helped carry the Chargers to an AFC divisional playoff matchup against the Pittsburgh Steelers on Sunday.

Sproles followed up a 115-yard rushing performance in the regular-season finale against Denver with 105 yards and two touchdowns on 23 carries in Saturday's playoff opener against Indianapolis, as the Chargers played the final 40 minutes without LaDainian Tomlinson.

Also catching five passes and returning four kickoffs and three punts that night, Sproles' 328 all-purpose yards were the third-most in NFL playoff history.

Now a guy who can be lost in a huddle of large humanity on the field fills the cover of the Sports Illustrated that hits newsstands today.

And even as he prepares for at least one more game as a Charger, wherein he will almost certainly make his first start in place of the injured Tomlinson, Sproles' potential as an every-down back is suddenly the hot topic in the NFL.

Sproles has just 106 carries in the NFL, including 61 this season and 37 in 2007, as coach Norv Turner has carefully used him.

But the fact is, playing in the Big 12, he averaged 20 carries a game and 6.1 yards a carry over his final three seasons (39 games). He averaged 5.4 yards a carry this season and also averaged 11.8 yards on 29 receptions.

“It's the stuff I've seen constantly,” said his agent, Gary Wichard. “All he's done is maintain what he's always done.”

Go ahead and take that as a hint as to what Wichard thinks Sproles' role can be in the NFL.

Sproles, who recently said he wants to remain in San Diego, declined to talk about the future. Asked specifically about the future, Wichard said only, “We've got a long way to go. He's just got to keep doing his thing.”

Sproles sees himself as a back capable of carrying a team's running load.

“Yeah,” he said when asked if he was an every-down back. What he has done this season, he said, “gives me the confidence to know I can do it” at this level.